Library of Congress. Copyright Office, Supplementary Copyright Statutes…
“ Even if you conclude that a work is in the public domain in the United States, this does not necessarily mean that you are free to use it in other countries. Every nation has its own laws governing the length and scope of copyright protection, and these are applicable to uses of the work within that nation's borders. Thus, the expiration or loss of copyright protection in the United States may still leave the work fully protected against unauthorized use in other countries. ”
